1. Field of the Invention
The present invention relates to an elevator door unit, and more particularly, to an elevator door unit having a mechanism which manually releases a lock unit of a cage in an emergency such as a power failure.
2. Description of the Related Art
A cage of an elevator may make an emergency stop in sections other than a landing hall of a building when a power failure or other emergency conditions occurs. A passenger in the cage may open the cage door by force. If the cage door is opened forcibly from the inside of the cage, passengers will be exposed to danger. For example, passengers may fall into a shaft. Particularly, an elevator for viewing the outside has an open part where a cage is not surrounded by shaft walls. If a cage makes an emergency stop in this open part and a cage door is opened by force, passengers will be exposed to more danger. Therefore, a cage door is configured not to be opened forcibly from the inside of a cage.
In some elevator, the inside atmospheric pressure of a cage is controlled. A cage is airtight. When an elevator makes an emergency stop because of a power failure or other accidents, a cage door can be manually opened a little to let fresh air into a cage. However, if a cage door should be opened wide, passengers will be exposed to danger of falling, and the opening width of a cage door must be strictly limited.
An elevator is provided with a cage door lock unit. The cage door lock unit locks a cage door by limiting the cage door opening width, so that passengers are not exposed to danger even if a passenger attempts to open the cage door from inside.
The cage door lock unit has a lock pin driven by a solenoid as a driving source. The lock pin is urged by a spring so as to project in one direction. When electricity is applied to the solenoid, the solenoid moves the lock pin against the spring, and unlocks the cage door. In case of emergency such as a power failure or other accidents, the lock pin is pushed out by the spring, and the cage door is held locked.
A gate is provided in a landing hall of each floor of a building. A hall door is provided in each gate. The hall door is provided with a hall door lock unit.
An elevator has an engagement unit. When a cage arrives at a certain floor and a cage door coincides with a hall door, the engagement unit engages the cage door with the hall door. The lock of the hall door lock unit is released by the mechanical operation caused by this engagement. An electric signal is generated by the release of the hall door lock unit, and based on this electric signal, electricity is applied to the solenoid of the cage door lock unit. As a result, the lock pin is driven and the lock of the cage door is released. The cage door is provided with a drive unit. When the drive unit is operated, the cage door is opened together with the hall door. Then, passengers can get on or off the cage.
After passengers get on or off, the cage door and hall door are closed by the drive unit. When the hall door is completely closed, the hall door lock unit operates mechanically to lock the hall door. An electric signal is generated by locking the hall door, and the application of electricity to the solenoid is stopped by this electric signal. The lock pin is urged by the spring to lock the cage door.
If the cage should be stopped at a position where the cage door does not coincide with the hall door in case of emergency, the cage door is prevented by the cage door lock unit from being opened forcibly by a passenger. Even in the case of emergency stop, as long as the cage door coincides with the hall door, the cage door lock unit can be manually operated and unlocked from the landing hall side. The cage door lock unit is unlocked by the manual operation using a push member which pushes mechanically the lock pin. Passengers confined in the cage are rescued by unlocking the cage door lock unit from the landing hall side.
However, even if the cage stops in an emergency at a position where the cage coincides with the hall door, passengers in the cage cannot unlock the cage door lock unit and escape from the cage by their own efforts. The passengers left in the cage must wait for rescue from the outside. Particularly, when a cage stops under emergency conditions such as an earthquake and fire, passengers are confined in the cage and cannot escape from the cage, though the cage is stopping at the landing hall.